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HomeMy WebLinkAboutWORTHINGTON STORAGE - PDP220003 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORT PRELIMINARY DRAINAGE REPORT WORTHINGTON SELF STORAGE MAY 18, 2022 NORTHERNENGINEERING.COM 970.221.4158 FORT COLLINS GREELEY This Drainage Report is consciously provided as a PDF. Please consider the environment before printing this document in its entirety. When a hard copy is necessary, we recommend double-sided printing. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY COVER LETTER May 18, 2022 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, CO 80521 RE: PRELIMINARY DRAINAGE REPORT FOR WORTHINGTON SELF STORAGE Dear Staff: Northern Engineering is pleased to submit this Preliminary Drainage Report for your review. This report accompanies the combined Preliminary Plan submittal for the proposed Worthington Self Storage project. This report has been prepared in accordance with the City of Fort Collins Stormwater Criteria Manual (FCSCM) and serves to document the stormwater impacts associated with the proposed Worthington Enclosed Self Storage project. We understand that review by the City of Fort Collins is to assure general compliance with standardized criteria contained in the manual. If you should have any questions as you review this report, please feel free to contact us. Sincerely, NORTHERN ENGINEERING SERVICES, INC. MASON RUEBEL, PE Project Engineer NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY TABLE OF CONTENTS TABLE OF CONTENTS I. I. GENERAL LOCATION AND DESCRIPTION .......................................................... 1 II. II. DRAINAGE BASINS AND SUB-BASINS ............................................................... 4 III. III. DRAINAGE DESIGN CRITERIA .......................................................................... 4 IV. IV. DRAINAGE FACILITY DESIGN ........................................................................... 7 V. V. CONCLUSIONS .............................................................................................. 8 VI. VI. REFERENCES .............................................................................................. 10 TABLES AND FIGURES FIGURE 1: AERIAL PHOTOGRAPH ........................................................................................... 2 FIGURE 2: REGULATORY FLOODPLAINS ................................................................................ 3 TABLE 1: DETENTION POND SUMMARY ................................................................................. 8 TABLE 2: CHAMBER COUNT SUMMARY .................................................................................. 8 APPENDICES APPENDIX A – HYDROLOGIC COMPUTATIONS APPENDIX B – HYDRAULIC COMPUTATIONS APPENDIX C – DETENTION POND & WATER QUALITY COMPUTATIONS APPENDIX D – EROSION CONTROL REPORT APPENDIX E – USDA SOILS REPORT APPENDIX F – EXCERPTS FROM CENTRE FOR ADVANCED TECHNOLOGY 16TH FILING MAP POCKET DR1 – DRAINAGE EXHIBIT NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 1 | 11 I. GENERAL LOCATION AND DESCRIPTION A. LOCATION Vicinity Map Figure 1: Vicinty Map Worthington Self Storage project is located in the southwest quarter of Section 23, Township 7 North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. The project site is bordered to the east by Worthington Circle. The rest of the site is surrounded by a private road and commercial development apart of the Centre for Advanced Technology 10th & 19th Filing. The nearest existing major streets to the project are Worthington Circle and Centre Ave just to the north of the project site. A 15” storm sewer conveys stormwater from the existing project site to the north in an existing piping system along Centre Avenue outletting into Spring Creek. B. DESCRIPTION OF PROPERTY The existing project site comprises of ± 3.2 acres. The existing site will be subdivided into two lots with the proposed development on Lot 1 (1.98ac) and the existing building remaining in Lot 2 (1.22ac). NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 2 | 11 The site is currently used as asphalt parking lot with an adjacent 1-story existing building. A subsurface exploration report was completed by Triax Engineering, Inc. on June 4, 2021 (Triax Project No. D21G125). According to Triax Engineering, the site generally consists of clayey sand with groundwater at around 20-ft in depth. Underground detention chambers are proposed with this project. There will be approximately 15-ft of separation from the bottom of the system to groundwater level measured in the Soils report. ADS does not have a separation requirement as water is designed to flow freely between the system and adjacent soils. Groundwater levels would only affect total storage volume. According to the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soil Survey website: (http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx), the site consists primarily of Nunn Clay loam (Hydrologic Soil Group C) and Kim loam (Hydrologic Soil Group B). The calculations assume a Hydrologic Soil Group of C. Hydrologic Soil Group C has a slow rate of water absorption and infiltration. The proposed development will consist of proposed 3-story enclosed mini-storage building and three other 1-story outdoor garage storage buildings. Other proposed improvements include asphalt drive aisles, sidewalks, and landscaping. There is no increase in impervious area with the proposed project. Existing detention facilities and conveyance methods will be modified and updated to meet the current Fort Collins requirements. This includes modifying the existing detention pond and the addition of underground chambers. Figure 1: Aerial Photograph NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 3 | 11 The site is currently zoned as Employment District (E) in Fort Collins. Developments surrounding the project site are zoned as Employment as well and Neighborhood commercial district to the east of Worthington Circle. The proposed uses for the project are consistent with Employment District (E). Per the Centre for Advanced Technology 10th & 16th Filing Final Drainage and Erosion Control Study, the calculated detention volume is 1.51ac-ft which includes runoff from C.A.T 10th and the adjacent Worthington Circle. The detention storage volume is currently divided between a small detention pond and ponding in the adjacent parking lot through a series of area inlets. There is an existing 15” storm sewer in the northeast corner of the project site with a manhole and restrictor plate down-stream of the existing detention pond. The required release rate per the previous drainage report is 1.91cfs (2-yr historic). The current release rate will be maintained, but the existing detention and conveyance will be updated to meet the current Fort Collins requirements. Stormwater is conveyed to the north to the storm network in Centre Avenue and is ultimately discharged into Spring Creek. FLOODPLAIN The subject property is not located in a FEMA or City of Fort Collins regulatory floodplain. Figure 2: Regulatory Floodplains NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 4 | 11 II. DRAINAGE BASINS AND SUB-BASINS A. MAJOR BASIN DESCRIPTION Worthington Self Storage is within the City of Fort Collins Spring Creek major drainage basin which is centrally located in Fort Collins. The Spring Creek drainage basin extends from Horsetooth Reservoir to the confluence with the Poudre River. It encompasses 9 square miles in central Fort Collins. The basin is dominated by residential development, but also includes open space and areas of commercial development. B. SUB-BASIN DESCRIPTION The outfall for the project site is Spring Creek via the existing 15” storm sewer at the corner of Worthington Circle and the private access road. Per the C.A.T 16th Filing drainage report the existing 15” storm sewer and restrictor plate were sized to convey the calculated 2-yr historic flow (1.91cfs) and ultimately discharges to Spring Creek. The existing crown of Worthington Circle is the existing spill way for the detention. The existing spillway elevation is maintained and relocated to the onsite detention pond. Emergency overflow will maintain the same path to Centre Ave. The existing site can be defined with three (3) sub-basins. These include the drainage from the Centre for Advanced Technology (C.A.T) 10th Filing, Worthington Circle public ROW and the project site, C.A.T 16th Filing. The site does receive notable surface runoff from adjacent properties and is detained and released per the Centre for Advanced Technology 16th Filing Final Drainage and Erosion Control Study. Flows from C.A.T 10th Filing, and Worthington Circle will be conveyed through the proposed site and detention volume will be provided onsite. An existing detention volume of 1.51acft was calculated per the C.A.T 16th Filing report which is currently divided between an existing detention pond and ponding in the adjacent parking lot. Detention storage will be updated to current Fort Collins requirements, but the release rate will be maintained. There is no increase in impervious area with the proposed project and historic versus proposed impervious areas are documented within Appendix C. With the modification in impervious area LID and water quality treatment will be included with the drainage design. Water quality will also be designed to include Lot 2 of the project site to allow for future development of the rest of the property without additional stormwater facilities. III. DRAINAGE DESIGN CRITERIA A. OPTIONAL REVISIONS There are no optional provisions outside of the Fort Collins Stormwater Manual (FCSM) B. STORMWATER MANAGEMENT STRATEGY The overall stormwater management strategy employed with Worthington Self Storage utilizes the “Four Step Process” to minimize adverse impacts of urbanization on receiving waters. The following is a description of how the proposed development has incorporated each step. Step 1 – Employ Runoff Reduction Practices. The first consideration taken in trying to reduce the stormwater impacts of this development is the site selection itself. By choosing an already developed site with public storm sewer currently in place, the burden is significantly less than developing a vacant parcel absent of any infrastructure. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 5 | 11 Worthington Self Storage aims to reduce runoff peaks, volumes and pollutant loads from frequently occurring storm events (i.e., water quality (i.e., 80th percentile) and 2-year storm events) by implementing Low Impact Development (LID) strategies. Wherever practical, runoff will be routed across landscaped areas or through underground chambers. These LID practices reduce the overall amount of impervious area, while at the same time Minimizing Directly Connected Impervious Areas (MDCIA). The combined LID/MDCIA techniques will be implemented, where practical, throughout the development, thereby slowing runoff and increasing opportunities for infiltration. Step 2 – Implement BMPs that Provide a Water Quality Capture Volume (WQCV) with Slow Release. The efforts taken in Step 1 will help to minimize excess runoff from frequently occurring storm events; however, urban development of this intensity will still have stormwater runoff leaving the site. The primary water quality treatment will occur in underground chambers and extended detention pond. Step 3 – Stabilize Drainageways. As stated in Section II.A, above, the site discharges into Spring Creek, however no changes to the channel are proposed with this project. While this step may not seem applicable to Worthington Self Storage, the proposed project indirectly helps achieve stabilized drainageways, nonetheless. Once again, site selection has a positive effect on stream stabilization. By developing with existing stormwater infrastructure, combined with LID and MDCIA strategies, the likelihood of bed and bank erosion is reduced. Furthermore, this project will pay one- time stormwater development fees, as well as ongoing monthly stormwater utility fees, both of which help achieve Citywide drainageway stability. Step 4 – Implement Site Specific and Other Source Control BMPs. The proposed project will provide site specific source controls and improve on historic conditions. Localized trash enclosures within the development will contain and allow for the disposal of solid waste. Standard Operating procedures (SOPs) will be implemented for BMP maintenance of detention ponds, underground chambers, and associated drainage infrastructure to remove sediment accumulation regularly and prolong the design life of the BMPs. C. DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS The subject property is part of a Master Drainage Plan for The Centre for Advanced Technology development. An Overall Development Plan (ODP) drainage study is also submitted concurrently with this project. However, stormwater from Worthington Self Storage will generally follow historic patterns and discharge into conveyance structures established as part of the Centre for Advanced Technology 16th Filing. The subject property is an “in-fill” development project as the property is surrounded by currently developed properties and private access roads. The existing 15-inch storm drain will function as the ultimate outfall for the project site. D. HYDROLOGICAL CRITERIA The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure 3.4-1 of the FCSCM, serve as the source for all hydrologic computations associated with Worthington Self Storage development. Tabulated data contained in Table 3.4-1 has been utilized for Rational Method runoff calculations. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 6 | 11 The Rational Method has been employed to compute stormwater runoff utilizing coefficients contained in Tables 3.2-1, 3.2-2, and 3.2-3 of the FCSCM. The Rational Method will be used to estimate peak developed stormwater runoff from drainage basins within the developed site for the 2-year, 10-year, and 100-year design storms. Peak runoff discharges determined using this methodology have been used to check the street capacities, inlets, swales, and storm drain lines. Two separate design storms have been utilized to address distinct drainage scenarios. The first event analyzed is the “Minor” or “Initial” Storm with a 2-year recurrence interval. The second event considered is the “Major Storm” with a 100-year recurrence interval. E. HYDRAULIC CRITERIA The hydraulic analyses of street capacities, inlets, storm drain lines, culverts, and swales will be per the FCSM criteria and provided during Final Plan. The following computer programs and methods will be utilized: · The storm drain lines will be analyzed using the Hydraflow Express Extension for AutoCAD Civil 3D. · The inlets will be analyzed using the Urban Drainage Inlet and proprietary area inlet spreadsheets. · Swales and street capacities will be analyzed using the Urban Drainage Channels spreadsheets. F. FLOODPLAIN REGULATIONS COMPLIANCE As previously mentioned, this project is not subject to any floodplain regulations. G. MODIFICATIONS OF CRITERIA No formal modifications are requested at this time. H. CONFORMANCE WITH WATER QUALITY TREATMENT CRITERIA City Code requires that 100% of runoff from a project site receive some sort of water quality treatment. This project proposes to provide the majority of water quality treatment with underground chambers. The chambers, when constructed per Fort Collins regulations, are considered an LID treatment method. Due to the physical constraints associated with a project and flows from adjacent properties there is a small area that cannot be captured with the underground chambers. Treatment of this area will be provided with extended detention within the proposed detention pond. An exhibit is provided in Appendix C detailing treatment areas and methods. I. CONFORMANCE WITH LOW IMPACT DEVELOPMENT (LID) The project site will conform with the requirement to treat a minimum of 75% of the project site using a LID technique. LID treatment will be provided by underground chambers. Please see Appendix C for LID design information, table, and exhibit(s). As shown in the LID table provided in the appendix, Lot 1 will treat 83% of the proposed site impervious area, which exceeds the minimum required. LID treatment will be provided for 100% of Lot 2, to allow for future development of the rest of the site without additional drainage facilities. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 7 | 11 IV. DRAINAGE FACILITY DESIGN A. GENERAL CONCEPT The main objective of Worthington Storage drainage design is to maintain existing drainage patterns, while not adversely impacting adjacent properties. There is off-site flows into the existing property that will be accounted for in the basins described below. A list of tables and figures used within this report can be found in the Table of Contents at the front of the document. The tables and figures are located within the sections to which the content best applies. Drainage for the project site has been analyzed using six (6) drainage sub-basins. The drainage patterns anticipated for the basins are further described below. Basin A1 Basin A1 is approximately 0.63 acres and consists of the detention pond, surrounding landscaping areas and a portion of the parking lot in the northeast corner of the site. The basin will generally maintain historic drainage patterns. Runoff from this basin will flow into the onsite detention pond and backup into the proposed underground chambers for additional storage. Offsite flow from C.A.T 10th Filing is conveyed in a concrete pan from the north and collected in a proposed curb inlet. The detention ponds will provide both detention for the surrounding basins and water quality in the form of extended (40-hour) detention for just this basin. The detention pond will discharge into the existing 15-inch storm drain outfall. Basin A2 Basin A2 is approximately 1.37 acres and consists of a portion of the proposed building and existing cinema saver building. Runoff from this basin will sheet flow to valley pans in the center of the proposed private access roads. Flow will be collected by an area inlet and discharge into underground chambers. Offsite flow from Basin OS2 is conveyed via cub & gutter and concrete pan from the west and collected in the proposed area inlet. A water quality weir will be installed, and water quality treatment will be provided for 100% of basin A2. Detention will be provided by a combination of underground chambers and detention ponds. Basin A3 Basin A2 is approximately 1.14 acres and consists of a portion of the proposed building and existing cinema saver building. Runoff from this basin will sheet flow to valley pans in the center of the proposed private access roads. Flow will be collected by area inlets and discharge into underground chambers. A water quality weir will be installed, and water quality treatment will be provided for 100% of basin A3. Detention will be provided by a combination of underground chambers and detention ponds. Basin OS1 Basin OS1 is approximately 2.04 acres. This basin consists of the existing Centre for Advanced Technology 10th filing development. The basin will maintain historic drainage patterns from northwest to southeast. Runoff from this basin will sheet flow from the existing structures and parking lots and collect in an existing concrete pan which will tie NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 8 | 11 into Basin A1 and discharge into a proposed curb inlet. Detention will be provided for this basin in the proposed detention ponds and underground chambers. Basin OS2 Basin OS2 is approximately 1.57 acres and consists of the existing residential buildings along Shields St and a portion of a private access road along the west side of the site. The basin will generally maintain historic drainage patterns from the southwest to the northeast. Runoff from this basin will sheet flow and collect in a proposed area inlet in basins A2. Detention will be provided for basin in the proposed underground chambers and detention ponds. Basin OS3 Basin OS3 is approximately 0.7 acres and consists of Worthington Circle. The basin will generally maintain historic drainage patterns. Runoff from this basin will collect in the existing curb and gutter and discharge into two existing type R inlets at the north corner of the project site. These inlets tie into the proposed detention pond. Detention will be provided for this basin in the proposed detention pond and underground chambers. A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report. B. SPECIFIC DETAILS The Worthington Self Storage project will be utilizing a combination of two detention ponds and 142 MC-3500 Stormtech chambers to fullfill their stormwater detention and treatment requirements. Worthington Self Storage will be providing 100% WQCV using LID measures and extended detention. Detention Summary Required Water Quality Volume (Pond) 0.01 ac-ft Required Water Quality Volume (Chambers) 0.12 ac-ft Required Detention Volume 1.61 ac-ft Design Volume 1.63 ac-ft Existing Release Rate 1.91 cfs Table 1: Detention Pond Summary MC-3500 Chamber Counts Detention WQCV Total 254 30 284 Table 2: Chamber Count Summary Final design details, detailed hydraulic calculations, and construction documentation, will be provided to the City of Fort Collins for review prior to Final Development Plan approval. V. CONCLUSIONS A. COMPLIANCE WITH STANDARDS The proposed drainage design for the Worthington Self Storage complies with the City of Fort Collins Stormwater Criteria Manual. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 9 | 11 The drainage design proposed complies with the City of Fort Collins’ Master Drainage Plan for the Spring Creek Basin. The proposed drainage design complies with the Master Drainage Plan for the existing Centre for Advanced Technology Development (CAT). There are no regulatory floodplains associated with the development The drainage plan and stormwater measurements proposed with Worthington Self Storage are compliant with all applicable State and Fedaral regulations. B. DRAINAGE CONCEPT 1. The drainage design proposed with this project will effectively limit any potential damage or erosion associated with its stormwater runoff. All existing downstream drainage facilities are expected to not be impacted negatively by this development. 2. The Worthington Storage project will maintain the release rate per the CAT 16th Filing Drainage Report. The existing drainage design has been updated to current City of Fort Collins Standards. 3. This project site provides 100% water quailty treatment through two methods. The site meets the requirements set forth by the City of Fort Collins for Low Impact Development (LID) by providing 86% total impervious area being treated through LID treatment. Standard water quailty treatement is provided for the remaining Area (Basin A1) through extended detention. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: WORTHINGTON SELF STORAGE FORT COLLINS | GREELEY 10 | 11 VI. REFERENCES 1. City of Fort Collins Landscape Design Guidelines for Stormwater and Detention Facilities, November 5, 2009, BHA Design, Inc. with City of Fort Collins Utility Services. 2. Final Drainage and Erosion Control Study for Cinema Savers Centre for Advanced Technology Sixteenth Filing., RBD, Inc., Fort Collins, Colorado, March 22, 1994. 3. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No. 159, 2018, and referenced in Section 26-500 of the City of Fort Collins Municipal Code. 4. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United States Department of Agriculture. 5. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright-McLaughlin Engineers, Denver, Colorado, Revised April 2008. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX APPENDIX A HYDROLOGIC COMPUTATIONS Runoff Coefficient1 Percent Impervious1 Project: Location: 0.95 100%Calc. By: 0.95 90%Date: 0.85 90% 0.55 50% 0.20 2% 0.20 2% Basin ID Basin Area (sq.ft.) Basin Area (acres)Asphalt (sq. ft.) Concrete (Sq. Ft.) Asphalt, Concrete (sq.ft.) Asphalt, Concrete (acres)Rooftop (sq.ft.) Rooftop (acres) Lawns, Clayey Soil, Flat Slope < 2% (sq.ft.) Lawns, Clayey Soil, Flat Slope < 2% (acres) Percent Impervious C2*Cf Cf = 1.00 C5*Cf Cf = 1.00 C10*Cf Cf = 1.00 C100*Cf Cf = 1.25 A1 27,568 0.63 10966 944 11910 0.27 1,805 0.04 13,853 0.32 50% 0.57 0.57 0.57 0.72 A2 59,866 1.37 23080 3592 26672 0.61 24,541 0.56 8,653 0.20 82% 0.84 0.84 0.84 1.00 A3 49,770 1.14 14141 3299 17440 0.40 26,636 0.61 5,694 0.13 83% 0.86 0.86 0.86 1.00 OS1 88,927 2.04 44464 0 44464 1.02 10,987 0.25 33,476 0.77 62% 0.67 0.67 0.67 0.83 OS2 68,407 1.57 12776 0 12776 0.29 7,812 0.18 47,819 1.10 30% 0.43 0.43 0.43 0.53 OS3 30,483 0.70 24567 0 24567 0.56 0 0.00 5,916 0.14 81% 0.80 0.80 0.80 1.00 A1-OS3 325,021 7.46 129994 7835 137829 3.16 71,781 1.65 115,411 2.65 63% 0.68 0.68 0.68 0.85 DEVELOPED RUNOFF COEFFICIENT CALCULATIONS Asphalt, Concrete Rooftop Residential: High Density Residential: Low Density Streets, Parking Lots, Roofs, Alleys, and Drives: Character of Surface:Worthington Storage Fort Collins M. Ruebel May 18, 2022 Combined Basins Offsite Basins Lawns and Landscaping: 2) Composite Runoff Coefficient adjusted per Table 3.2-3 of the Fort Collins Stormwater Manual (FCSM). Lawns, Clayey Soil, Flat Slope < 2% USDA SOIL TYPE: C Undeveloped: Greenbelts, Agriculture Composite Runoff Coefficient2 1) Runoff coefficients per Tables 3.2-1 & 3.2 of the FCSM. Percent impervious per Tables 4.1-2 & 4.1-3 of the FCSM. Where: n = Roughness Coefficient R = Hydraulic Radius (feet) S = Longitudinal Slope, feet/feet Length (ft) Slope (%) Ti 2-Yr (min) Ti 10-Yr (min) Ti 100-Yr (min) Length (ft) Slope (%)Surface n Flow Area3 (sq.ft.) WP3 (ft)R (ft)V (ft/s) Tt (min) Max. Tc (min) Comp. Tc 2-Yr (min) Tc 2-Yr (min) Comp. Tc 10-Yr (min) Tc 10-Yr (min) Comp. Tc 100- Yr (min) Tc 100-Yr (min) a1 A1 20 2.00%3.50 3.50 2.55 50 3.00%Gutter 0.02 3.61 19.18 0.19 5.65 0.15 10.39 3.64 5.00 3.64 5.00 2.69 5.00 a2 A2 25 2.00%1.92 1.92 0.74 200 0.50%Valley Pan 0.02 6.00 10.25 0.59 4.92 0.68 11.25 2.60 5.00 2.60 5.00 1.42 5.00 a3 A3 166 2.00%4.51 4.51 1.91 80 0.50%Valley Pan 0.02 6.00 10.25 0.59 4.92 0.27 11.37 4.78 5.00 4.78 5.00 2.18 5.00 os1 OS1 160 2.00%8.12 8.12 4.98 190 1.00% Valley Pan 0.02 6.00 10.25 0.59 6.95 0.46 11.94 8.57 8.57 8.57 8.57 5.44 5.44 os2 OS2 150 1.33%14.03 14.03 11.82 190 3.79% Gutter 0.02 3.61 19.18 0.19 6.35 0.50 11.89 14.53 11.89 14.53 11.89 12.31 11.89 os3 OS3 20 2.00%1.96 1.96 0.66 340 1.00% Gutter 0.02 3.61 19.18 0.19 3.26 1.74 12.00 3.70 5.00 3.70 5.00 2.40 5.00 NotesV = Velocity (ft/sec) WP = Wetted Perimeter (ft) DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Location: Maximum Tc:Overland Flow, Time of Concentration: Channelized Flow, Velocity:Channelized Flow, Time of Concentration: Worthington Storage Fort Collins M. Ruebel May 18, 2022 Project: Calculations By: Date: Offsite Basins Design Point Basin ID Overland Flow Channelized Flow Time of Concentration (Equation 3.3-2 per Fort Collins Stormwater Manual) =1.87 1.1 − ∗ =1.49 ∗ /∗(Equation 5-4 per Fort Collins) =180 + 10 (Equation 3.3-5 per Fort Collins Stormwater Manual) =∗ 60 (Equation 5-5 per Fort Collins 1) Add 4900 to all elevations. 2) Per Fort Collins Stormwater Manual, minimum Tc = 5 min. 3) Assume a water depth of 6" and a typical curb and gutter per Larimer County Urban Street Standard Detail 701 for curb and gutter channelized flow. Assume a water depth of 1', fixed side slopes, and a triangular swale section for grass channelized flow. Assume a water depth of 1', 4:1 side slopes, and a 2' wide valley pan for channelized flow in a valley pan. Intensity, I from Fig. 3.4.1 Fort Collins Stormwater ManualRational Equation: Q = CiA (Equation 6-1 per MHFD)Tc2Tc10Tc100C2C10C100I2I10I100Q2Q10Q100a1A10.635.05.05.00.60.60.72.94.910.01.01.84.5a2A21.375.05.05.00.80.81.02.94.910.03.35.613.7a3A31.145.05.05.00.90.91.02.94.910.02.84.811.4os1 OS1 2.048.6 8.6 5.4 0.7 0.70.82.4 4.0 10.0 3.2 5.5 17.0os2 OS2 1.5711.9 11.9 11.9 0.4 0.40.52.1 3.6 7.3 1.4 2.4 6.1os3 OS3 0.705.0 5.0 5.0 0.8 0.81.02.9 4.9 10.0 1.6 2.7 7.0Offsite BasinsDate:Fort CollinsProject:Location:Calc. By:DEVELOPED DIRECT RUNOFF COMPUTATIONSIntensity (in/hr)Flow (cfs)Worthington StorageM. RuebelMay 18, 2022DesignPointBasinArea(acres)Runoff CTc (Min) NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX APPENDIX B HYDRAULIC COMPUTATIONS NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX Additional hydraulic calculations will be provided during final design. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX APPENDIX C DETENTION POND & WATER QUALITY COMPUTATIONS Pond ID Required Detention Volume (cf) Required Water Quality Volume (cf) Required Total Volume (cf) Design Detention Volume (cf) Design Water Quality Volume (cf) Design Total Volume (cf) Detention Pond 23086 566 23652 23086 566 23652 Stormtech Chambers 47044 5250 52294 48047 5250 53297 Total 70254 5816 76070 71133 5816 76949 254 12 10 8 284Total Detention & Water Quailty Summary MC-3500 CHAMBER COUNTS Detention Basin A2 - LID Basin A3 - LID Basin OS2 - LID NNORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX DETENTION FACILITIES Date:05/17/22 Pond No.: A1 100-yr WQCV 566 ft3 0.85 Quantity Detention 70254 ft3 7.46 acres Total Volume 70820 ft3 1.91 cfs Total Volume 1.626 ac-ft Time Time Ft.Collins 100-yr Intensity Q100 Inflow (Runoff) Volume Outflow (Release) Volume Storage Detention Volume (mins) (secs) (in/hr) (cfs) (ft3) (ft 3) (ft 3) 5 300 9.95 63.1 18928 573 18355 10 600 7.72 49.0 29372 1146 28226 15 900 6.52 41.3 37209 1719 35490 20 1200 5.60 35.5 42612 2292 40320 25 1500 4.98 31.6 47367 2865 44502 30 1800 4.52 28.7 51590 3438 48152 35 2100 4.08 25.9 54330 4011 50319 40 2400 3.74 23.7 56917 4584 52333 45 2700 3.46 21.9 59238 5157 54081 50 3000 3.23 20.5 61444 5730 55714 55 3300 3.03 19.2 63404 6303 57101 60 3600 2.86 18.1 65287 6876 58411 65 3900 2.72 17.2 67265 7449 59816 70 4200 2.59 16.4 68977 8022 60955 75 4500 2.48 15.7 70766 8595 62171 80 4800 2.38 15.1 72440 9168 63272 85 5100 2.29 14.5 74057 9741 64316 90 5400 2.21 14.0 75673 10314 65359 95 5700 2.13 13.5 76986 10887 66099 100 6000 2.06 13.1 78375 11460 66915 105 6300 2.00 12.7 79897 12033 67864 110 6600 1.94 12.3 81190 12606 68584 115 6900 1.89 12.0 82693 13179 69514 120 7200 1.84 11.7 84006 13752 70254 Detention Pond Calculation | FAA Method Project: Project Location: Calculations By: Worthington Storage Fort Collins, Colorado M. Ruebel 1 Developed "C" = Area (A)= Max Release Rate = Input Variables Results Design Point Required Detention Volume Design Storm 1 Project: Date: Pond No.: 4,945.20 0.53 ac. ft. Spillway Elev.:4,952.00 5,052.00 5,053.00 1.00 ft. Max. Elev. Min. Elev. cu. ft. acre ft cu. ft. acre ft 5,045.20 N/A 72.06 0.00 0.00 0.00 0.00 0.00 5,045.40 5,045.20 1,114.33 0.20 222.87 0.01 222.87 0.01 5,045.60 5,045.40 2,282.84 0.20 339.72 0.01 562.58 0.01 5,045.80 5,045.60 2,474.67 0.20 475.75 0.01 1,038.33 0.02 5,046.00 5,045.80 2,504.50 0.20 497.92 0.01 1,536.25 0.04 5,046.20 5,046.00 2,532.63 0.20 503.71 0.01 2,039.96 0.05 5,046.40 5,046.20 2,560.73 0.20 509.34 0.01 2,549.30 0.06 5,046.60 5,046.40 2,588.52 0.20 514.92 0.01 3,064.22 0.07 5,046.80 5,046.60 2,615.81 0.20 520.43 0.01 3,584.66 0.08 5,047.00 5,046.80 2,643.41 0.20 525.92 0.01 4,110.58 0.09 5,047.20 5,047.00 2,670.97 0.20 531.44 0.01 4,642.02 0.11 5,047.40 5,047.20 2,698.12 0.20 536.91 0.01 5,178.93 0.12 5,047.60 5,047.40 2,725.42 0.20 542.35 0.01 5,721.28 0.13 5,047.80 5,047.60 2,808.74 0.20 553.42 0.01 6,274.70 0.14 5,048.00 5,047.80 3,048.37 0.20 585.71 0.01 6,860.41 0.16 5,048.20 5,048.00 3,430.80 0.20 647.92 0.01 7,508.32 0.17 5,048.40 5,048.20 3,526.96 0.20 695.78 0.02 8,204.10 0.19 5,048.60 5,048.40 3,567.79 0.20 709.47 0.02 8,913.58 0.20 5,048.80 5,048.60 3,604.91 0.20 717.27 0.02 9,630.85 0.22 5,049.00 5,048.80 3,639.44 0.20 724.43 0.02 10,355.28 0.24 5,049.20 5,049.00 3,673.17 0.20 731.26 0.02 11,086.54 0.25 5,049.40 5,049.20 3,707.31 0.20 738.05 0.02 11,824.59 0.27 5,049.60 5,049.40 3,740.62 0.20 744.79 0.02 12,569.38 0.29 5,049.80 5,049.60 3,773.25 0.20 751.39 0.02 13,320.77 0.31 5,050.00 5,049.80 3,806.22 0.20 757.95 0.02 14,078.72 0.32 5,050.20 5,050.00 3,839.26 0.20 764.55 0.02 14,843.26 0.34 5,050.40 5,050.20 3,961.42 0.20 780.07 0.02 15,623.33 0.36 5,050.60 5,050.40 4,280.98 0.20 824.24 0.02 16,447.57 0.38 5,050.80 5,050.60 4,707.42 0.20 898.84 0.02 17,346.41 0.40 5,051.00 5,050.80 4,778.51 0.20 948.59 0.02 18,295.01 0.42 5,051.20 5,051.00 4,821.29 0.20 959.98 0.02 19,254.99 0.44 5,051.40 5,051.20 4,863.51 0.20 968.48 0.02 20,223.47 0.46 5,051.60 5,051.40 4,905.21 0.20 976.87 0.02 21,200.34 0.49 5,051.80 5,051.60 4,946.52 0.20 985.17 0.02 22,185.51 0.51 5,052.00 5,051.80 4,987.25 0.20 993.38 0.02 23,178.89 0.53 Crest of Pond Elev.: Detention Pond Project Number: Project Location: Calculations By: Outlet Elevation:Design Volume: Detention Pond 1 STAGE STORAGE CURVE Contour Contour Surface Area (ft2) Depth (ft) Incremental Volume Cummalitive Volume Pond Stage Storage Curve 1853-001 Fort Collins, Colorado M. Ruebel Elev at Design Volume: Worthington Storage May 18, 2022 Pond Outlet and Volume Data Freeboard: 1 User Inputs Chamber Model: MC-3500 Outlet Control Structure: No Project Name: Red Rocks Self Stor- age copy Engineer: Mason undefined Project Location: Colorado Measurement Type: Imperial Required Storage Volume: 47741 cubic ft. Stone Porosity: 40% Stone Foundation Depth: 12 in. Stone Above Chambers: 12 in. Average Cover Over Chambers: 18 in. Design Constraint Dimensions:(500 ft. x 500 ft.) Results System Volume and Bed Size Installed Storage Volume: 48047.87 cubic ft. Storage Volume Per Chamber: 109.90 cubic ft. Number Of Chambers Required: 254 Number Of End Caps Required: 8 Chamber Rows: 4 Maximum Length:468.90 ft. Maximum Width: 29.17 ft. Approx. Bed Size Required: 13577.21 square ft. System Components Amount Of Stone Required: 1853.15 cubic yards Volume Of Excavation (Not Including Fill): 2891.44 cubic yards Total Non-woven Geotextile Required:4384.30 square yards Woven Geotextile Required (excluding Isolator Row): 50.19 square yards Woven Geotextile Required (Isolator Row): 539.49 square yards Total Woven Geotextile Required:589.68 square yards SSSCVAULTELECSSSELECCELECEDDDTCONTROLIRRGXXVAULTF.O.XXX X X X XXXXXXXXSSSCVAULTELECSSSELECCELECEDDDTCONTROLIRRGXXVAULTF.O.DRAWN BY:SCALE:DATE:EXISTING VS PROPOSEDIMPERVIOUS AREASHEET NO:FORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631ENGINEERNGIEHTRONRN970.221.4158northernengineering.comP:\1853-001\DWG\DRNG\1853-001_IMPV.DWG 2525 WORTHINGTON MINI-STORAGEFORT COLLINSCOLORADOMCREXISTINGPROPOSED( IN FEET )01 INCH = 60 FEET6060ROOFTOPCONCRETEASPHALTSURFACEAREA (SF)% IMPERV.IMPERV.AREA (SF)19,2207,17986,223100%100%100%112,622TOTAL=19,2207,17986,223GRAVEL040%01" = 60'5/18/2022IMP 1LANDSCAPING27,0230%0ROOFTOPCONCRETEASPHALTSURFACEAREA (SF)% IMPERV.IMPERV.AREA (SF)52,9838,35249,971100%100%100%111,306TOTAL=52,9838,35249,971GRAVEL040%0LANDSCAPING28,3390%0WO R T H I N G T O N C I R C L E WO R T H I N G T O N C I R C L E Project:Calc. By: Location:Date: Surface Area (SF)% Imperv.Imperv. Area (SF) Surface Area (SF)% Imperv.Imperv. Area (SF) Rooftop 19,220 100%19,220 Rooftop 52,983 100%52,983 Concrete 7,179 100%7,179 Concrete 8,352 100%8,352 Asphalt 86,223 100%86,223 Asphalt 49,971 100%49,971 Gravel 0 40%0 Gravel 0 40%0 Landscaping 27,023 0%0 Landscaping 28,339 0%0 Total 139,645 112,622 Total 139,645 111,306 -1,316 Existing Proposed Additional Impervious Area (SF) Onsite Impervious Areas Worthington Storage M. Ruebel Fort Collins, Colorado 05/18/22 Total Onsite Impervious Area NNORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX WATER QUALITY CALCULATIONS UD UD UD UD UDUD UDUDUDUDUDUDUD UD UD UD UD UDUDUDUDUDUDUDUDUDUDUDUDUDUDUDTFEUDXX X X X X XXXXXXXXCVAULTELECELECCELECEDDTCONTROLIRRGXXVAULTF.O.a1a3a22.04 ac.OS11.57 ac.OS20.63 ac.A11.37 ac.A21.14 ac.A30.70 ac.OS3OS3OS1OS2DRAWN BY:SCALE:DATE:LID EXHIBITSHEET NO:FORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631ENGINEERNGIEHTRONRN970.221.4158northernengineering.comP:\1853-001\DWG\DRNG\1853-001_LID_ALT1.DWG WORTHINGTON ENCLOSED MINI-STORAGEFORT COLLINSCOLORADOMCR1" = 60'5/5/2022LID 1W O R T H I N G T O N C I R C L E PROPOSED STORM SEWERPROPOSED CURB & GUTTERPROPERTY BOUNDARYPROPOSED INLETADESIGN POINTDRAINAGE BASIN LABELDRAINAGE BASIN BOUNDARYALEGEND:FOR DRAINAGE REVIEW ONLYNOT FOR CONSTRUCTION( IN FEET )1 inch = ft.Feet0606060STORMTECH CHAMBERSPROPOSED INLETw/ WQ WEIRPROPOSED INLETw/ WQ WEIRPROPOSED CURB INLETSTORMTECH CHAMBERS (ISOLATOR ROW)LOT 1LOT 2LID Site Summary - Total SiteTotal Area137,204ft2Total Impervious Area104,183ft2Total Impervious Area without LID Treatment13,784ft2A1Total Treated Area*90,399ft2Percent Impervious Treated by LID86.77%*Remaining Impervious area (Basin A1) treated by water quailty structure in Detention PondLID Summary per LID StructureLID IDAreaWeighted %ImperviousSubbasin IDTreatment TypeVolume perUD-BMP(ft3)Vol. w/20%Increase perFort CollinsManual (ft3)ImperviousArea (ft2)Sq. Ft.AcresStormtech A259,8661.3782%A2Stormtech1,3581,62949,090Stormtech A349,7701.1483%A3Stormtech1,1521,38241,309Total109,6362.523,01190,399PROPOSED BASINw/ WQ WEIRPROPOSED BASINw/ WQ WEIRPROPOSEDWATER QUALITYSTRUCTURESTORMTECH A2(ISOLATOR ROW)STORMTECH A3(ISOLATOR ROW)Water Quality Treatment SummaryBasinWQCV(ft3)SummaryA1566Standard Water Quality (EDB)A21629LID (Underground Chamber)A31382LID (Underground Chamber)OS10n/aOS2829LID (Underground Chamber)OS30n/aMC-3500 CHAMBER COUNTSDetention254Basin A2 - LID12Basin A3 - LID10Basin OS2 - LID8Total284 Project Number:Project: Project Location: Calculations By:Date: Sq. Ft. Acres A1 27,568 0.63 50%n/a n/a 0 13,784 A2 59,866 1.37 82%Stormtech A2 Stormtech 3,011 49,090 A3 49,770 1.14 83% Stormtech A3 Stormtech 3,011 41,309 Total 137,204 3.15 104,183 Project Number:Project: Project Location: Calculations By:Date: Sq. Ft. Acres Stormtech A2 59,866 1.37 82% A2 Stormtech 1,358 1,629 49,090 Stormtech A3 49,770 1.14 83% A3 Stormtech 1,152 1,382 41,309 Total 109,636 2.52 3,011 90,399 137,204 ft2 104,183 ft2 13,784 ft2 90,399 ft2 86.77% Subbasin ID Treatment TypeLID ID Volume per UD-BMP (ft3) Area Weighted % Impervious 1853-001 Worthington Storage Fort Collins, Colorado M.Ruebel 2/23/2022 LID Summary LID Summary per LID Structure Impervious Area (ft2) Vol. w/20% Increase per Fort Collins Manual (ft3) LID Summary AreaBasin ID Treatment TypePercent Impervious LID ID Worthington Storage 5/18/2022 1853-001 Fort Collins, Colorado M. Ruebel Total Impervious Area (ft2) Required Volume (ft3) LID Summary per Basin Total Treated Area* Percent Impervious Treated by LID *Remaining Impervious area (Basin A1) treated by water quailty structure in Detention Pond LID Site Summary - Total Site Total Area Total Impervious Area Total Impervious Area without LID Treatment A1 Project: Calc. By: Date: 0.63 <-- INPUT from impervious calcs 50%<-- INPUT from impervious calcs 0.50 <-- CALCULATED 40 hours <-- from FCSM Figure 5.4-1 1.00 <-- from FCSM Figure 5.4-1 0.21 <-- MHFD Vol. 3 Equation 3-1 0.01 <-- FCSCM Equation 7-2 566 <-- Calculated from above **<-- INPUT from stage-storage table **<-- CALCULATED from Equation EDB-3 dia (in) =** number of columns=** number of rows =** number of holes =** Area Per Row =** Total Outlet Area (in2) =**<-- CALCULATED from total number of holes WQCV (watershed inches) = WATER QUALITY POND DESIGN CALCULATIONS Water Quality for Detention Pond Worthington Storage M. Ruebel May 18, 2022 Required Storage & Outlet Works Basin Area (acres) = Basin Percent Imperviousness = Basin Imperviousness Ratio = Drain Time = Drain Time Coefficient = **To be completed at final design WQCV (ac-ft) = WQ Depth (ft) = Area Required Per Row, a (in 2) = Circular Perforation Sizing WQCV (cu. ft.) = NORTHERNENGINEERING.COM | 970.221.4158 FORT COLLINS | GREELEY Project Title Date: Project Number Calcs By: City Basins 0.8 WQCV = Watershed inches of Runoff (inches)82% a = Runoff Volume Reduction (constant) i = Total imperviousness Ratio (i = Iwq/100)0.273 in A =1.37 ac V = 0.0312 ac-ft V = Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) 1629 cu. ft. Drain Time a = i = WQCV = Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event Worthington Storage May 17, 2022 1853-001 M. Ruebel Fort Collins Stormtech Chambers 1 (Lot 1) 0.231 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr ()iii78.019.10.91aWQCV 23 +-= ()iii78.019.10.91aWQCV 23 +-= AV* 12 WQCV   = 12 hr Pond No : A2, WQ 1.00 5.00 min 1229 ft3 1.37 acres 0.03 ac-ft Max Release Rate =0.41 cfs Time (min) Ft Collins WQ Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor QWQ (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 1.425 586 1.00 0.41 123 463 10 1.105 908 1.00 0.41 246 662 15 0.935 1153 0.67 0.27 246 907 20 0.805 1323 0.63 0.26 308 1016 25 0.715 1469 0.60 0.25 369 1100 30 0.650 1603 0.58 0.24 431 1172 35 0.585 1683 0.57 0.23 492 1191 40 0.535 1759 0.56 0.23 554 1206 45 0.495 1831 0.56 0.23 615 1216 50 0.460 1891 0.55 0.23 677 1214 55 0.435 1967 0.55 0.22 738 1229 60 0.410 2022 0.54 0.22 800 1223 65 0.385 2057 0.54 0.22 861 1196 70 0.365 2100 0.54 0.22 923 1178 75 0.345 2127 0.53 0.22 984 1143 80 0.330 2170 0.53 0.22 1046 1125 85 0.315 2201 0.53 0.22 1107 1094 90 0.305 2256 0.53 0.22 1169 1088 95 0.290 2265 0.53 0.22 1230 1035 100 0.280 2302 0.53 0.22 1292 1010 105 0.270 2330 0.52 0.21 1353 977 110 0.260 2351 0.52 0.21 1415 936 115 0.255 2411 0.52 0.21 1476 935 120 0.245 2417 0.52 0.21 1538 879 *Note: Using the method described in FCSCM Chapter 6 Section 2.3 A = Tc = Project Location : Design Point C = Design Storm DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 1853-001 Worthington Storage Project Number : Project Name : Stormtech Chambers A2 Page 2 of 5 1853-001 Chamber Summary_A2_alt1 Vault IDTotal RequiredWQ Volume(cf)Flow,WQ(cfs)ChamberTypeChamber Release Ratea(cfs)ChamberVolumeb(cf)Installed Chamber w/ Aggregatec(cf)Mimimum No. of ChambersdTotal Release Ratee(cfs)Required Storage Volume by FAA Method(cf)Mimimum No. of ChambersfProvided Number of Chambers Provided Release Rate (cfs)Storage Provided within the Chambersg(cf)Total Installed System Volumeh(cf)Chamber A2 1629 1.65 MC-3500 0.038 109.90 175.00 10 0.38 122912 12 0.451319 2100a. Release rate per chamber, limited by flow through geotextile with accumulated sediment. Q=0.0022(cfs/sf)*(Floor Area of Chamber)*Flow rate based on 1/2 of Nov 07 QMAX in Figure 17 of UNH Testing Reportb. Volume within chamber only, not accounting for void spaces in surrounding aggregate.c. Volume includes chamber and void spaces (40%) in surrounding aggregate, per chamber unit.d. Number of chambers required to provide full WQCV within total installed system, including aggregate.e. Release rate per chamber times number of chambers.f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage).g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume.h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV.Chamber Configuration SummaryP:\1853-001\Drainage\LID\1853-001 Chamber Summary_A2_alt1 Project Title Date: Project Number Calcs By: City Basins 0.8 WQCV = Watershed inches of Runoff (inches)83% a = Runoff Volume Reduction (constant) i = Total imperviousness Ratio (i = Iwq/100)0.278 in A =1.14 ac V = 0.0264 ac-ft V = Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) 1382 cu. ft. Drain Time a = i = WQCV = Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event Worthington Storage May 17, 2022 1853-001 M. Ruebel Fort Collins Stormtech Chambers A3 0.231 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr ()iii78.019.10.91aWQCV 23 +-= ()iii78.019.10.91aWQCV 23 +-= AV* 12 WQCV   = 12 hr Pond No : A3 WQ 1.00 5.00 min 1067 ft3 1.22 acres 0.02 ac-ft Max Release Rate =0.38 cfs Time (min) Ft Collins WQ Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor QWQ (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 1.425 522 1.00 0.38 114 408 10 1.105 809 1.00 0.38 228 581 15 0.935 1027 0.67 0.25 228 799 20 0.805 1179 0.63 0.24 285 894 25 0.715 1308 0.60 0.23 342 966 30 0.650 1427 0.58 0.22 399 1028 35 0.585 1499 0.57 0.22 456 1043 40 0.535 1566 0.56 0.21 513 1053 45 0.495 1631 0.56 0.21 570 1061 50 0.460 1684 0.55 0.21 627 1057 55 0.435 1751 0.55 0.21 684 1067 60 0.410 1801 0.54 0.21 741 1060 65 0.385 1832 0.54 0.20 798 1034 70 0.365 1870 0.54 0.20 855 1015 75 0.345 1894 0.53 0.20 912 982 80 0.330 1932 0.53 0.20 969 963 85 0.315 1960 0.53 0.20 1026 934 90 0.305 2009 0.53 0.20 1083 926 95 0.290 2017 0.53 0.20 1140 877 100 0.280 2050 0.53 0.20 1197 853 105 0.270 2075 0.52 0.20 1254 821 110 0.260 2094 0.52 0.20 1311 783 115 0.255 2147 0.52 0.20 1368 779 120 0.245 2152 0.52 0.20 1425 727 *Note: Using the method described in FCSCM Chapter 6 Section 2.3 A = Tc = Project Location : Design Point C = Design Storm DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 1853-001 Worthington Storage Project Number : Project Name : Stormtech Chambers A3 Page 2 of 5 1853-001 Chamber Summary_A3-alt1 Vault IDTotal RequiredWQ Volume(cf)Flow,WQ(cfs)ChamberTypeChamber Release Ratea(cfs)ChamberVolumeb(cf)Installed Chamber w/ Aggregatec(cf)Mimimum No. of ChambersdTotal Release Ratee(cfs)Required Storage Volume by FAA Method(cf)Mimimum No. of ChambersfProvided Number of Chambers Provided Release Rate (cfs)Storage Provided within the Chambersg(cf)Total Installed System Volumeh(cf)Chamber A3 1382 1.40 MC-3500 0.038 109.90 175.00 8 0.30 106710 10 0.381099 1750a. Release rate per chamber, limited by flow through geotextile with accumulated sediment. Q=0.0022(cfs/sf)*(Floor Area of Chamber)*Flow rate based on 1/2 of Nov 07 QMAX in Figure 17 of UNH Testing Reportb. Volume within chamber only, not accounting for void spaces in surrounding aggregate.c. Volume includes chamber and void spaces (40%) in surrounding aggregate, per chamber unit.d. Number of chambers required to provide full WQCV within total installed system, including aggregate.e. Release rate per chamber times number of chambers.f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage).g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume.h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV.Chamber Configuration SummaryP:\1853-001\Drainage\LID\1853-001 Chamber Summary_A3-alt1 Project Title Date: Project Number Calcs By: City Basins 0.8 WQCV = Watershed inches of Runoff (inches)30% a = Runoff Volume Reduction (constant) i = Total imperviousness Ratio (i = Iwq/100)0.121 in A =1.57 ac V = 0.0159 ac-ft V = Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) Worthington Storage May 17, 2022 1853-001 M. Ruebel Fort Collins Stormtech Chambers OS2 829 cu. ft. Drain Time a = i = WQCV = Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event 0.231 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr ()iii78.019.10.91aWQCV 23 +-= ()iii78.019.10.91aWQCV 23 +-= AV* 12 WQCV   = 12 hr Pond No : OS2 WQ 0.59 5.00 min 790 ft3 1.57 acres 0.02 ac-ft Max Release Rate =0.30 cfs Time (min) Ft Collins WQ Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor QWQ (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 1.425 396 1.00 0.30 90 306 10 1.105 614 1.00 0.30 180 434 15 0.935 779 0.67 0.20 180 599 20 0.805 895 0.63 0.19 225 670 25 0.715 993 0.60 0.18 270 723 30 0.650 1084 0.58 0.18 315 769 35 0.585 1138 0.57 0.17 360 778 40 0.535 1189 0.56 0.17 405 784 45 0.495 1238 0.56 0.17 450 788 50 0.460 1278 0.55 0.17 495 783 55 0.435 1330 0.55 0.16 540 790 60 0.410 1367 0.54 0.16 585 782 65 0.385 1391 0.54 0.16 630 761 70 0.365 1420 0.54 0.16 675 745 75 0.345 1438 0.53 0.16 720 718 80 0.330 1467 0.53 0.16 765 702 85 0.315 1488 0.53 0.16 810 678 90 0.305 1526 0.53 0.16 855 671 95 0.290 1531 0.53 0.16 900 631 100 0.280 1556 0.53 0.16 945 611 105 0.270 1576 0.52 0.16 990 586 110 0.260 1590 0.52 0.16 1035 555 115 0.255 1630 0.52 0.16 1080 550 120 0.245 1634 0.52 0.16 1125 509 *Note: Using the method described in FCSCM Chapter 6 Section 2.3 DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 1853-001 Worthington Storage Project Number : Project Name : Stormtech Chambers OS2 A = Tc = Project Location : Design Point C = Design Storm Page 2 of 5 1853-001 Chamber Summary_OS2_alt1 Vault IDTotal RequiredWQ Volume(cf)Flow,WQ(cfs)ChamberTypeChamber Release Ratea(cfs)ChamberVolumeb(cf)Installed Chamber w/ Aggregatec(cf)Mimimum No. of ChambersdTotal Release Ratee(cfs)Required Storage Volume by FAA Method(cf)Mimimum No. of ChambersfProvided Number of Chambers Provided Release Rate (cfs)Storage Provided within the Chambersg(cf)Total Installed System Volumeh(cf)Chamber OS2 829 0.70 MC-3500 0.038 109.90 175.00 5 0.19 7908 8 0.30879 1400a. Release rate per chamber, limited by flow through geotextile with accumulated sediment. Q=0.0022(cfs/sf)*(Floor Area of Chamber)*Flow rate based on 1/2 of Nov 07 QMAX in Figure 17 of UNH Testing Reportb. Volume within chamber only, not accounting for void spaces in surrounding aggregate.c. Volume includes chamber and void spaces (40%) in surrounding aggregate, per chamber unit.d. Number of chambers required to provide full WQCV within total installed system, including aggregate.e. Release rate per chamber times number of chambers.f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage).g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume.h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV.Chamber Configuration SummaryP:\1853-001\Drainage\LID\1853-001 Chamber Summary_OS2_alt1 NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX APPENDIX D EROSION CONTROL REPORT NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY EROSION CONTROL REPORT EROSION CONTROL REPORT A comprehensive Erosion and Sediment Control Plan (along with associated details) has been included with the final construction drawings. It should be noted; however, any such Erosion and Sediment Control Plan serves only as a general guide to the Contractor. Staging and/or phasing of the BMPs depicted, and additional or different BMPs from those included may be necessary during construction, or as required by the authorities having jurisdiction. It shall be the responsibility of the Contractor to ensure erosion control measures are properly maintained and followed. The Erosion and Sediment Control Plan is intended to be a living document, constantly adapting to site conditions and needs. The Contractor shall update the location of BMPs as they are installed, removed, or modified in conjunction with construction activities. It is imperative to appropriately reflect the current site conditions at all times. The Erosion and Sediment Control Plan shall address both temporary measures to be implemented during construction, as well as permanent erosion control protection. Best Management Practices from the Volume 3, Chapter 7 – Construction BMPs will be utilized. Measures may include, but are not limited to, silt fencing and/or wattles along the disturbed perimeter, gutter protection in the adjacent roadways, and inlet protection at existing and proposed storm inlets. Vehicle tracking control pads, spill containment and clean-up procedures, designated concrete washout areas, dumpsters, and job site restrooms shall also be provided by the Contractor. Grading and Erosion Control Notes can be found on Sheet CS2 of the Utility Plans. The Final Utility Plans will also contain a full-size Erosion Control Plan as well as a separate sheet dedicated to Erosion Control Details. In addition to this report and the referenced plan sheets, the Contractor shall be aware of, and adhere to, the applicable requirements outlined in any existing Development Agreement(s) of record, as well as the Development Agreement, to be recorded prior to issuance of the Development Construction Permit. Also, the Site Contractor for this project may be required to secure a Stormwater Construction General Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division – Stormwater Program, before commencing any earth disturbing activities. Prior to securing said permit, the Site Contractor shall develop a comprehensive Storm Water Management Plan (SWMP) pursuant to CDPHE requirements and guidelines. The SWMP will further describe and document the ongoing activities, inspections, and maintenance of construction BMPs. NNORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX APPENDIX E USDA SOILS REPORT United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Larimer County Area, Colorado Worthington Storage Natural Resources Conservation Service February 17, 2022 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................11 Map Unit Descriptions.........................................................................................11 Larimer County Area, Colorado......................................................................13 73—Nunn clay loam, 0 to 1 percent slopes.................................................13 74—Nunn clay loam, 1 to 3 percent slopes.................................................14 References............................................................................................................16 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 4489180448920044892204489240448926044892804489300448932044893404489360448938044891804489200448922044892404489260448928044893004489320448934044893604489380491910 491930 491950 491970 491990 492010 492030 492050 491910 491930 491950 491970 491990 492010 492030 492050 40° 33' 18'' N 105° 5' 44'' W40° 33' 18'' N105° 5' 37'' W40° 33' 11'' N 105° 5' 44'' W40° 33' 11'' N 105° 5' 37'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 15 30 60 90 Meters Map Scale: 1:1,070 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 16, Sep 2, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 11, 2018—Aug 12, 2018 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 10 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 73 Nunn clay loam, 0 to 1 percent slopes 0.0 1.1% 74 Nunn clay loam, 1 to 3 percent slopes 3.1 98.9% Totals for Area of Interest 3.1 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, Custom Soil Resource Report 11 onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Larimer County Area, Colorado 73—Nunn clay loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: 2tlng Elevation: 4,100 to 5,700 feet Mean annual precipitation: 14 to 15 inches Mean annual air temperature: 48 to 52 degrees F Frost-free period: 135 to 152 days Farmland classification: Prime farmland if irrigated Map Unit Composition Nunn and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn Setting Landform:Terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Pleistocene aged alluvium and/or eolian deposits Typical profile Ap - 0 to 6 inches: clay loam Bt1 - 6 to 10 inches: clay loam Bt2 - 10 to 26 inches: clay loam Btk - 26 to 31 inches: clay loam Bk1 - 31 to 47 inches: loam Bk2 - 47 to 80 inches: loam Properties and qualities Slope:0 to 1 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:7 percent Maximum salinity:Nonsaline (0.1 to 1.0 mmhos/cm) Sodium adsorption ratio, maximum:0.5 Available water supply, 0 to 60 inches: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: C Ecological site: R067BY042CO - Clayey Plains Hydric soil rating: No Custom Soil Resource Report 13 Minor Components Heldt Percent of map unit:10 percent Landform:Terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Ecological site:R067BY042CO - Clayey Plains Hydric soil rating: No Wages Percent of map unit:5 percent Landform:Terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Ecological site:R067BY002CO - Loamy Plains Hydric soil rating: No 74—Nunn clay loam, 1 to 3 percent slopes Map Unit Setting National map unit symbol: 2tlpl Elevation: 3,900 to 5,840 feet Mean annual precipitation: 13 to 17 inches Mean annual air temperature: 50 to 54 degrees F Frost-free period: 135 to 160 days Farmland classification: Prime farmland if irrigated Map Unit Composition Nunn and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn Setting Landform:Terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Pleistocene aged alluvium and/or eolian deposits Typical profile Ap - 0 to 9 inches: clay loam Bt - 9 to 13 inches: clay loam Btk - 13 to 25 inches: clay loam Bk1 - 25 to 38 inches: clay loam Bk2 - 38 to 80 inches: clay loam Custom Soil Resource Report 14 Properties and qualities Slope:1 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:7 percent Maximum salinity:Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum:0.5 Available water supply, 0 to 60 inches: High (about 9.9 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: C Ecological site: R067BY042CO - Clayey Plains Hydric soil rating: No Minor Components Heldt Percent of map unit:10 percent Landform:Terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Ecological site:R067BY042CO - Clayey Plains Hydric soil rating: No Satanta Percent of map unit:5 percent Landform:Terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Ecological site:R067BY002CO - Loamy Plains Hydric soil rating: No Custom Soil Resource Report 15 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. 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U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 17 NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX APPENDIX F EXCERPTS FROM CENTRE FOR ADVANCED TECHNOLOGY 16TH FILING NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: TIMBER LARK RESIDENTIAL FORT COLLINS | GREELEY APPENDIX MAP POCKET DR1 – DRAINAGE EXHIBIT APPENDIX F REFERENCE DOCUMENTS STSTSTSTSTSTSTSTSTSTC VAULT ELEC ELEC C ELEC E D FE SD D D T CONTROL IRR GXXX TTTTTTVAULT F.O. OS2 OWNER: TALL DENTIST LLC 1001 CENTRE AVE DODSANITY LLC 1013 CENTRE AVE (EMPLOYMENT DISTRICT) OWNER: KATSCH24 LLC 1007 CENTRE AVE OWNER: AWEIDA PROPERTIES INC 2500 S SHIELDS ST OWNER: AWEIDA PROPERTIES INC 2514 S SHIELDS ST OWNER: WARPAL LLC 1044 W DRAKE RD MARKET CENTRE RETAIL ASSOCIATION OWNER: TWO PAULS LLC 932 W DRAKE RD OWNER: ROBERT WILSON 2526 WORTHINGTON CIRCLE OWNER: COLUMBINE MEDICAL REAL ESTATE LLC 915 CENTRE AVE CENTRE AVENUE WO R T H I NG TO N C I R C L E S SHIELDS STREETP R I V A T E A C C E S S R O A DPRIVATE ACCESS ROADEXISTING DETENTION POND 1 PRIVA T E A C C E S S R O A D EXISTING BUILDING 2.27 ac. H1 4.81 ac. H2 0.43 ac. H3 OS1 OS3 EXISTING 15" RCP STORM DRAIN EXISTING STORM MANHOLE AND RESTRICTOR PLATE SheetThese drawings areinstruments of serviceprovided by NorthernEngineering Services, Inc.and are not to be used forany type of constructionunless signed and sealed bya Professional Engineer inthe employ of NorthernEngineering Services, Inc.NOT FOR CONSTRUCTIONREVIEW SETENGINEERNGIEHTRONRNFORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631970.221.4158northernengineering.comof 17WORTHINGTON SELF STORAGEDR1 HISTORIC DRAINAGE EXHIBIT16 PROPOSED CONTOUR PROPOSED STORM SEWER PROPOSED SWALE EXISTING CONTOUR PROPOSED CURB & GUTTER PROPERTY BOUNDARY PROPOSED INLET A DESIGN POINT FLOW ARROW DRAINAGE BASIN LABEL DRAINAGE BASIN BOUNDARY PROPOSED SWALE SECTION 11 NOTES: 1.REFER TO THE PRELIMINARY DRAINAGE REPORT, DATED MAY 18, 2022 FOR ADDITIONAL INFORMATION. A LEGEND: FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION NORTH ( IN FEET ) 0 1 INCH = 40 FEET 40 40 80 120 STSTSTS S S S C S S S C D D D T CONTROL IRR GXXX TTTTTT VAULT F.O.XXXX XXXXXXX X X X XXXXXXXXXFFFFFUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUD UD UD UD UDUDUD UD UD UD FUDUDUDU D UDU D U D UDU D U D U D F WIRUDa1 OWNER: TALL DENTIST LLC 1001 CENTRE AVE DODSANITY LLC 1013 CENTRE AVE (EMPLOYMENT DISTRICT) OWNER: KATSCH24 LLC 1007 CENTRE AVE OWNER: AWEIDA PROPERTIES INC 2500 S SHIELDS ST OWNER: AWEIDA PROPERTIES INC 2514 S SHIELDS ST OWNER: WARPAL LLC 1044 W DRAKE RD MARKET CENTRE RETAIL ASSOCIATION OWNER: TWO PAULS LLC 932 W DRAKE RD OWNER: ROBERT WILSON 2526 WORTHINGTON CIRCLE OWNER: COLUMBINE MEDICAL REAL ESTATE LLC 915 CENTRE AVE CENTRE AVENUE WO R T H I N G T O N C I R C L E S SHIELDS STREETP R I V A T E A C C E S S R O A DPRIVATE ACCESS ROADDETENTION POND PRIVA T E A C C E S S R O A D EXISTING BUILDING PROPOSED BUILDING 2.04 ac. OS1 1.57 ac. OS2 0.63 ac. A1 1.37 ac. A2 1.14 ac. A3 0.70 ac. OS3 os3 os1 os2 a3 a2 PROPOSED GARAGE EXISTING 15" RCP STORM DRAIN EXISTING STORM MANHOLE AND RESTRICTOR PLATE PROPOSED CURB INLET PROPOSED STORM DRAIN PROPOSED AREA INLET w/ WATER QUALITY WEIR PROPOSED CURB INLET w/ WATER QUALITY WEIR PROPOSED GARAGE PROPOSED GARAGE PROPOSED BASIN w/ WATER QUALITY WEIR PROPOSED BASIN w/ WATER QUALITY WEIR SheetThese drawings areinstruments of serviceprovided by NorthernEngineering Services, Inc.and are not to be used forany type of constructionunless signed and sealed bya Professional Engineer inthe employ of NorthernEngineering Services, Inc.NOT FOR CONSTRUCTIONREVIEW SETENGINEERNGIEHTRONRNFORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631970.221.4158northernengineering.comof 17WORTHINGTON SELF STORAGEDR2 DRAINAGE EXHIBIT17 PROPOSED CONTOUR PROPOSED STORM SEWER PROPOSED SWALE EXISTING CONTOUR PROPOSED CURB & GUTTER PROPERTY BOUNDARY PROPOSED INLET A DESIGN POINT FLOW ARROW DRAINAGE BASIN LABEL DRAINAGE BASIN BOUNDARY PROPOSED SWALE SECTION 11 NOTES: 1.REFER TO THE PRELIMINARY DRAINAGE REPORT, DATED MAY 18, 2022 FOR ADDITIONAL INFORMATION. A LEGEND: FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION NORTH ( IN FEET ) 0 1 INCH = 40 FEET 40 40 80 120 Design Point Basin Area (acres) Tc (Min)Runoff C Intensity (in/hr)Flow (cfs) Tc2 Tc10 Tc100 C2 C10 C100 I2 I10 I100 Q2 Q10 Q100 a1 A1 0.63 5.0 5.0 5.0 0.6 0.6 0.7 2.9 4.9 10.0 1.0 1.8 4.5 a2 A2 1.37 5.0 5.0 5.0 0.8 0.8 1.0 2.9 4.9 10.0 3.3 5.6 13.7 a3 A3 1.14 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 2.8 4.8 11.4 Offsite Basins os1 OS1 2.04 8.6 8.6 5.4 0.7 0.7 0.8 2.4 4.0 10.0 3.2 5.5 17.0 os2 OS2 1.57 11.9 11.9 11.9 0.4 0.4 0.5 2.1 3.6 7.3 1.4 2.4 6.1 os3 OS3 0.70 5.0 5.0 5.0 0.8 0.8 1.0 2.9 4.9 10.0 1.6 2.7 7.0 LID Site Summary - Total Site Total Area 137,204 ft2 Total Impervious Area 104,183 ft2 Total Impervious Area without LID Treatment 13,784 ft2 A1 Total Treated Area*90,399 ft2 Percent Impervious Treated by LID 86.77% *Remaining Impervious area (Basin A1) treated by water quailty structure in Detention Pond Water Quality Treatment Summary Basin WQCV(ft3)Summary A1 566 Standard Water Quality (EDB) A2 1629 LID (Underground Chamber) A3 1382 LID (Underground Chamber) OS1 0 n/a OS2 829 LID (Underground Chamber) OS3 0 n/a MC-3500 CHAMBER COUNTS Detention 254 Basin A2 - LID 12 Basin A3 - LID 10 Basin OS2 - LID 8 Total 284